Mangroves and coastal aquaculture.

Abstract

Abstract There is considerable concern over destruction of mangroves by shrimp farming and other types of aquaculture, and it is true that mangroves have been destroyed for installation of aquaculture ponds. In most countries, destruction of mangroves results from people seeking wood for building or for fuel. Also, mangroves may be destroyed for development unrelated to shrimp or other types of aquaculture. Worldwide, probably less than 10% of mangrove loss may be attributed to aquaculture, but in some countries, aquaculture is responsible for 20% or more of historic loss of mangroves. Mangrove areas are not ideal places for shrimp farming or other types of aquaculture. This is because of the following: low elevation, poor drainage characteristics, location in complex and sensitive ecosystems where it is difficult to prevent spread of aquatic animal diseases and where bird predation of culture species may be great, and the tendency of soils to have high organic matter concentrations and to be highly acidic from sulfide-sulfur oxidation. Thus, shrimp farms and other aquaculture activities in mangrove areas tend to be less productive than those in non-mangrove areas. Mangrove areas afford shelter from storms and provide biological treatment of pollution entering waters from various human activities. Thus, their destruction is harmful to aquaculture. It is no longer popular to locate aquaculture farms in mangroves and in most countries, governmental regulations make it illegal to do so. Areas behind mangrove forests often are excellent sites for aquaculture farms. Governments implementing regulations to exclude aquaculture activities from mangrove areas should allow shrimp and fish farmers to route water supply and discharge canals through mangrove areas and to locate pump stations in mangrove areas if necessary. It is possible to have aquaculture ponds and mangroves situated harmoniously in the same area, and management practices to encourage this objective are provided.